import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

docshell/base/timeline/DocLoadingTimelineMarker.h

@@ -0,0 +1,40 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_DocLoadingTimelineMarker_h_
+#define mozilla_DocLoadingTimelineMarker_h_
+
+#include "TimelineMarker.h"
+#include "mozilla/dom/ProfileTimelineMarkerBinding.h"
+
+namespace mozilla {
+
+class DocLoadingTimelineMarker : public TimelineMarker
+{
+public:
+  explicit DocLoadingTimelineMarker(const char* aName)
+    : TimelineMarker(aName, MarkerTracingType::TIMESTAMP)
+    , mUnixTime(PR_Now())
+  {}
+
+  virtual void AddDetails(JSContext* aCx, dom::ProfileTimelineMarker& aMarker) override
+  {
+    TimelineMarker::AddDetails(aCx, aMarker);
+    aMarker.mUnixTime.Construct(mUnixTime);
+  }
+
+private:
+  // Certain consumers might use Date.now() or similar for tracing time.
+  // However, TimelineMarkers use process creation as an epoch, which provides
+  // more precision. To allow syncing, attach an additional unix timestamp.
+  // Using this instead of `AbstractTimelineMarker::GetTime()'s` timestamp
+  // is strongly discouraged.
+  PRTime mUnixTime;
+};
+
+} // namespace mozilla
+
+#endif // mozilla_DocLoadingTimelineMarker_h_